Contaminated measures may also mask positive or negative effects of interventions.
Pleiotropic effects caused by ubiquitous expression of hUCP3 may be detrimental to lifespan, and may mask any positive, tissue-dependent effects of mitochondrial uncoupling.
Because birth order increases with parental age and, in this and other studies, has been found to be negatively associated with ASD risk, failure to control for birth order may mask a positive association between parental age and ASD risk.
However, such purifying selection may be masking positive selection of a small number of codons within the amplified fragments.
Values of ω > 1.0 are regarded as indicating that positive selection has operated on the sequences analyzed [ 12]; however, global substitution analysis is stringent and may mask evidence of positive selection in molecular subregions [ 13].
Because compensatory TCR rearrangements may mask a potential positive selection defect, we examined thymic development in blt/blt mice expressing the class II MHC-restricted OTII TCR transgene, in which impaired positive selection would be expected to cause a dramatic reduction in CD4SP thymocytes.
Large number of false positives, partly due to a low colony size cutoff, may mask some true positives; 5) screening strategy and criteria for target identification may need further refinement.
Otherwise, you may mask the effects - positive or negative - of your training programme".
Errors in classification may occur in an extensive field survey, as reported here, and a dynamic situation (i.e., the process of invasion of a new site) may mask the occurrence of some positive or potentially positive sites.
However, gene-wide estimates of dN/ dS which show overall purifying selection may mask a small number of sites experiencing positive selection.
